Chlorophyll+Analaysis

__Chlorophyll Results and soon other Nutrient Data__


 * Special Thanks to Dr. Troy Mutchler for his materials, lab space, and above all his time and expertise.**

__Why look at total chlorophyll?__

Chlorophyll derived from phytoplankton is important to better understand the water's chemistry that is often considered the health or quality of a body of water. These microscopic producers tell us how conditions are right then and there as they live, replicate and die in a short time span and thus react quickly to changes in the water chemistry. Thus if chlorophyll is plentiful it can be deduced conditions are favorable for algae and the inverse conditions would exist if chlorophyll was scarce. This is NOT to say that high chlorophyll is good and low is bad. These levels are useful as information as they can be correlated with the abiotic factors we measure to either support or refute ideas we have about the causes and effects of what we witness with our eyes, noses, and scientific gadgetry.

__Chlorophyll Methods and Materials__

Sites 2, 4 and 6 on long Island and Marsh creeks were chosen as the best representation of the two creeks. It would have been logistically unfeasible to collect and analyze samples from all 6 sites on each creek and these sites provided relatively evenly spaced sites with water volumes sufficient to collect from. The headwaters sites (1) wear limited by the amount of flowing water available at any given time.

Samples were collected mid stream, mid depth and in triplicate at each site. The samples were collected in pre labeled, pre cleaned, plastic 500ml bottles. These bottles were kept on ice and in the dark until and during processing and analyzing to prevent post extraction degradation of any pigments. A carefully regulated amount of the sample water was subjected to vacuum filtration through 0.7 micron glass fiber filters. These filters were then soaked in acetone for 18 hours in a -10 °C freezer and were then centrifuged at 4000 rpm for 10 minutes, decanted into a quartz crystal cuvette and subjected to photo spectroscopy. The absorbance was measured at 750nm and 665nm. The absorbance at 665nm is the absorbance maxima for the chlorophyll molecule and the absorbance at 750nm is taken and subtracted from the absorbance at 665nm to account for suspended solids in the supernatant. The % absorbance measured specific to chlorophyll is then multiplied by a coefficient (11) and the volume of acetone (5ml) used to extract it and this number is divided by the volume of water filtered (.125- .25L) and the path-length of the cuvette (1cm). The resulting quotient is the amount of chlorophyll in mg/L.

Total chlorophyll = 11.0(Abs665 – Abs750)v/Vp

The mean value of the three samples is then reported as the average total chlorophyll. This measurement is accepted as a sound indication to the amount of phytoplankton present in the water.

__Results, Graphs and Eye Candy__

Some patterns emerged with the chlorophyll data. One might expect a direct increase in chlorophyll as the streams became deeper, wider, and slower, aka downstream. This is because in theory the algae get more of what they want. Deeper is more habitat, wider means more sunlight or energy, and slower means more time in that energetic habitat. Of course slower is relative when compared with a headwaters site as sometimes there is water there and sometimes there is not. All the same that variable is avoided by not sampling the site 1's. Ok that's theory. The pattern we actually found is an expected increase from site 2 to site 4 but then wild variability in site 6. This holds true for both creeks but with peaks and troughs on different weeks. This information is graphically presented in the following figure.



Chlorophyll and Nutrient Data Comparisons

Comparison of different sample sites within the two creeks Figure 1. Mean concentration values for sites 2, 4, and 6 on Long Island Creek. Significant difference found between site LI2 and LI6 (a) for Nitrate concentrations, p= **0.003173**, and site LI2 and LI4 (b) for Chlorophyll concentrations, p=**0.008163.**



Figure 2. Mean concentration values for sites 2, 4, and 6 on Marsh Creek. Error bars for MC 2 Ammonia span from +7.8 to -2. Y axis formatted to maintain usable scale. Significant difference found between sites MC2 and MC4 chlorophyll concentrations, p= **0.046795**



Figure 3. Comparison of nutrient and chlorophyll between the 2 creeks. No statistically significant differences were found.



Correlations of Mean Chlorophyll values to Mean values of various Nutrients Figure 4. Mean Chlorophyll concentrations vs. Mean Phosphorous concentrations in both creeks. No significant correlation



Figure 5. Mean Chlorophyll concentrations as a function of Nitrate/Nitrite concentrations. No significant correlations.



Figure 6. Mean Chlorophyll concentrations as a function of Ammonia concentrations (mg/L). No significant correlations. One outlier removed to maintain scale.



Finally the Eye Candy

On 6-14-12 a plankton tow was taken at site 6 on both streams in order to sample the algae community. There was a wide variety of photosythetic and heterotrophic life suspended in the water and they look cool so below you will find pictures of just some of them.

First some filamentous greens



Spirogyra sp. **Aptly named eh.** // Aulacoseira // sp.

 Tribonema sp.

__http://www.proprofs.com/flashcards/upload/a2295904.jpg__

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Next some semi single greens called desmids, some single celled diatoms and a really ancient little creature, the eugleana.



Desmids Naviculasp. A Diatom

Euglena sp.

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And then a few of the non photosynthetic creatures from the streams

Mixed Rotifer drawings and an example of a live specimen. __ [] __ __ [] __

Introduction | Stakeholders | Water Quality | Urban Ecology | Land Use Mapping | Methods | Study Sites | Results Conclusions 
 * wherev is the volume (mL) of acetone used to extract the pigments; V is the volume (L) of water filtered; and p is the pathlength of the cuvette containing the sample (cm). ||